That's what my wife said too. Maybe one of my neighbors is putting stuff in my tank(from there own faucet). But I figured my 2 filters would have caught it.
It really depends on the type and quality of gas you use, generally the lower grade and quality can have something in it right from the pump, but at the same time, what ever additives the gas has can also be causing problems with the inside of your tank(s)/lines..... I remember back when my Father used to buy ARCO(Pre-BP) or 7-11(Pre-Citgo), and ours Cars & Suburb would have carb problems regularly... The In-Line Filter would always clog up, or the Jets would be severely gummed.... I would suggest you check your lines, and even inspect your tank(s) for any signs of problems..... It is possible that you are getting rust scale from the inside of the tank, but it could be just some contaminates from your Gas Station.... If it is a Fine Grit, it is possible that the In-line filter is old enough that it needs to be replaced, or the Gas additives is disolving it.....